Dual view endoscope

ABSTRACT

An endoscope is provided to examine internal organs with front and rear views. The endoscope comprises a shaft extending from a distal end in a rearward direction along a longitudinal axis towards a proximal end, with the distal and proximal ends defining a hollow channel extended there-through. The endoscope further comprises a first lens positioned adjacent to the distal end and configured to receive a first image in a forward direction along the longitudinal axis, with the forward direction generally 180 degree from the rearward direction. The endoscope further comprises a rearview module positioned adjacent to the distal end. The rearview module comprises a second lens configured to be positioned adjacent to the distal end, and receive a second image in a target direction having a directional component in the rearward direction along the longitudinal axis, independently of the first lens receiving the first image in the forward direction.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation application under 35 U.S.C. §120 ofU.S. Non-provisional patent application Ser. No. 10/711,859, filed onOct. 11, 2004, now issued to patent as U.S. Pat. No. 8,585,584, theentire disclosure of the aforesaid prior application being incorporatedherein by reference.

DESCRIPTION

Field of Invention

The present invention relates to endoscopes, more specifically toendoscopes that provide both forward and rear view in a hollow bodyorgan.

Background and Prior Art

Endoscopes are used to perform a variety of surgical procedures. FIGS. 1and 2 illustrate an embodiment of a conventional endoscope. It has ahandle from which extends a flexible shaft, which is inserted into ahollow organ to be inspected. The shaft consists of a proximal section,insertion tube, bending section and a stiff section. The shaftterminates in the distal end, which typically houses image lens,illumination bulb, air/water nozzle and an instrument channel outlet.Light is transmitted from a light source through the shaft via anelectric cable to the illumination bulb. The illumination bulbilluminates the area to be examined. The image lens captures images ofthe illuminated area. The image is then transmitted through a fiberoptic cable and viewed through an eyepiece on the handle of theendoscope. Alternatively, the image is converted to a video signal andtransmitted to an image processor by an electrical cable. The image isthen processed and displayed on a display unit like a computer monitor.The handle of the endoscope has an extension arm that attaches theendoscope to a light source and an image processor.

To enable the endoscope to maneuver through the turns of a hollow organthe shaft is flexible and incorporates a multitude of cables that attachthe bending portion with actuators. Tension is applied to these cablesto move the bending portion in various directions. This is done bymanual adjustment of actuators on the handle of the endoscope.Typically, there are two pairs of such cables passing within the shaft,one pair for flexing the bending portion in one plane and the other pairfor flexing it in an orthogonal plane.

It is also usual to provide two channels extending between the handleand the distal end of the shaft, an air/water channel and an instrumentchannel. The air/water channel is used to insufflate air in a holloworgan to expand it for proper visualization. The air/water channel isconnected proximally to an air/water pump (not shown) and to distally tothe air/water channel outlet. The image lens and the illumination bulbare frequently smeared with blood, stool or other body fluids while in ahollow organ which obstructs a clear view. In such a situation, theair/water channel is used to eject water or blow air at the image lensand/or illumination bulb in order to clean them while still inside ahollow organ. The instrument channel has an inlet proximally and anoutlet distally. It is used to pass various surgical instruments to dovarious surgical procedures. It is also used to apply suction to removefluids, air and other materials from within a hollow organ duringexamination.

Endoscope is typically inserted into the patient either thorough anatural body orifice like anus or mouth or it is inserted through asurgical incision. It is then steered to a desired location by adjustingthe bending portion and manually pushing the endoscope. After reachingthe desired location, the endoscope is withdrawn. Typically it is duringpullout when the inside of a hollow organ like colon is thoroughlyexamined. Insertion of the endoscope into a hollow organ is a riskymaneuver and is associated with significant complications like trauma,bleeding and perforation. It is generally desirable to complete theexamination with a single insertion to minimize complications.

The present endoscopes have significant limitations. As shown in FIG. 3they are only forward viewing. Currently, rear view can only be obtainedby bending the distal portion of the endoscope back upon itself in a‘retro flexion’ maneuver as shown in FIG. 4B. However, it is notpossible to achieve retro flexion in many narrow hollow organs likecolon, esophagus, duodenum and small bowel. Also, retro flexioncompromises forward view. Hence with conventional endoscopes, only oneview, forward or backward, is possible at a given time. The presentendoscopes also have a narrow field of vision with an angle of vision ofabout 120 degrees. A large number of significant pathologic findings arefrequently missed during endoscopic examination because the inability toobtain rear view and a narrow field of vision of conventionalendoscopes.

This is especially true for colonoscopy where the inside of the colon isexamined with an endoscope. Many cancers and pre cancerous lesions(polyps) are frequently missed during colonoscopy (Pickhardt et al, NewEngland Journal of Medicine 2003; 349: 2191-2200). This has seriousconsequences including death, many of which can easily be prevented.Majority of the missed lesions lie on the rear side of mucosal folds(Pickhardt et al; Annals of Internal Medicine 2004; 141: 352-360). Withforward viewing endoscopes, the front of mucosal folds obstructsvisualization of the rear side as shown in FIG. 4A. Currently, the rearside of a mucosal fold can only be examined by pushing the tip of theendoscope beyond the fold and bending the endoscope back upon itself ina ‘retro flexion’ maneuver as shown in FIG. 4B. However, it isfrequently not possible to achieve retro flexion in a narrow holloworgan like colon.

Also, retro flexion maneuver compromises the forward view. Withconventional endoscopes, only one view, forward or backward, is possibleat a given time. Complete examination of colon that includes bothforward and rear views currently requires multiple insertions, one toobtain forward view and other to obtain backward view by retro flexion.Both, retro flexion and multiple insertions, independently increase themorbidity, mortality, time and cost of colonoscopy. Moreover, intracolonic retro flexion can not be obtained frequently because of a narrowcolonic lumen. Also, conventional endoscopes have a narrow field ofvision of about 120 degrees. Some lesions that are missed lie outside ofthe field of view of conventional endoscopes.

The rear side of the mucosal folds is also hard to access withconventional endoscopes, which have the instrument channel outlet onlyon the distal end. These areas can only be visualized by retro flexion,which narrows and sometimes obliterates the lumen of the instrumentchannel. Also, many surgical instruments are not flexible enough tofollow the path of a retroflexed endoscope. It is difficult and manytimes impossible to pass surgical instruments through the instrumentchannel when the endoscope is retroflexed and surgical procedures cannot be performed on the rear side of the mucosal folds.

SUMMARY OF THE INVENTION

In light of the significant limitations discussed above, there is a needfor an endoscopic system that provides both forward and rear view andwidens the field of vision. It should also enable surgical procedures tobe done in areas that are otherwise inaccessible and lie outside offield of vision of the conventional endoscopes. The present inventionaddresses these unmet needs.

The present invention enables rear view even in organs with a narrowlumen without the need to retro flex the endoscope. This is achieved bystrategically adding a suitably designed ‘rear view module’ to aconventional endoscope. The rear view module consists of a rear imagelens and a rear illumination bulb. The rear view module is a solid ortubular structure that can be of different shapes, sizes andconfigurations as illustrated in the preferred embodiments of thepresent invention. It is attached to the endoscope in different ways asillustrated in the preferred embodiments of the present invention. Oncedeployed, the rear view module positions the rear image lens and therear illumination bulb facing backward. In this position, the rearillumination bulb illuminates the rear area and the rear image lensgives a rear view. The rear image lens is connected to an imageprocessor and the rear illumination bulb is connected to a power sourceby electrical cables. The rear image lens and the rear illumination bulbcan be used simultaneously or separately from the main image lens andthe main illumination bulb, as chosen by the operator. Simultaneousforward and rear view can thus be obtained by using the forward imagelens and the rear image lens together at a given time. This has theadvantage of allowing a thorough examination of a hollow organ thatincludes both forward and rear views in a single passage.

The present invention has a rear instrument channel and a rearinstrument channel outlet. The rear instrument channel is connected tothe main instrument channel and the connecting passage has a controlvalve. Typically deployment of the rear view module automatically opensthe passage to the rear instrument channel. Alternatively, the valve canhave an independent control. The rear instrument channel is used to passsurgical instruments to do various surgical procedures in areas thatwould otherwise be inaccessible. It also enables the operator to directsuction in areas under the view of the rear image lens.

The present invention has a rear air/water channel and a rear air/waternozzle located on the shaft of the endoscope. The rear air/water channelis connected to the main air/water channel of the endoscope and theconnecting passage has a control valve. Typically, deployment of therear view module automatically opens the passage to the rear air/waterchannel. Alternatively, the valve can be controlled independently. Therear air/water channel enables the operator to insufflate air anddistend the area under the view of rear image lens. Adequate distensionof a hollow organ is essential to obtain a clear and complete view. Therear air/water channel also provides a water jet and a stream of air toclean the rear image lens and rear illumination bulb while inside ahollow body organ.

Additional features and advantages of the present invention will be setforth in the description and drawings which follow or may be learned bypractice of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a view of a conventional endoscope.

FIG. 2 shows a side view of the distal end, bending section andinsertion tube of a conventional endoscope.

FIG. 3 is a side view of a conventional endoscope displaying the fieldof vision of a conventional endoscope.

FIG. 4A shows a conventional endoscope inside a colon. It shows mucosalfolds of the colon and illustrates that visualization of the area behindmucosal folds is obstructed by the front of the mucosal folds duringexamination with a conventional endoscope.

FIG. 4B shows a conventional endoscope inside a colon in a retroflexedposition. It displays how retro flexion enables visualization of areabehind a mucosal fold.

FIG. 5 shows side view of an endoscope with the ‘rear view module’according to a first embodiment of the present invention.

FIG. 6 shows side view of the endoscope in FIG. 5 wherein the ‘rear viewmodule’ is deployed for rear view.

FIG. 7 shows side view of an endoscope with the ‘rear view module’according to a second embodiment of the present invention.

FIG. 8 shows side view of the endoscope in FIG. 7 wherein the ‘rear viewmodule’ is deployed for rear view.

FIG. 9 shows side view of an endoscope with a ‘rear view module’according to a third embodiment of the present invention.

FIG. 10 is a side view of the endoscope in FIG. 9 wherein the ‘rear viewmodule’ is deployed for rear view.

FIG. 11 shows side view of an endoscope with a ‘rear view module’according to a fourth embodiment of the present invention.

FIG. 12 shows side view of the endoscope in FIG. 11 wherein the ‘rearview module’ is deployed for rear view.

FIG. 13 shows side view of an endoscope with a ‘rear view module’according to a fifth embodiment of the present invention.

FIGS. 14-16 is a side view of the endoscope in FIG. 13 wherein the ‘rearview module’ is deployed for rear view.

FIG. 17 shows side view of a ‘rear view module’ according to a sixthembodiment of the present invention.

FIGS. 18 & 19 shows side view of the endoscope in FIG. 17 wherein the‘rear view module’ is deployed for rear view.

FIG. 20 shows side view of an endoscope with a ‘rear view module’according to a seventh embodiment of the present invention.

FIG. 21 is a side view of the endoscope in FIG. 20 wherein the ‘rearview module’ is deployed for rear view.

FIG. 22 shows side view of an endoscope with a ‘rear view module’according to an eighth embodiment of the present invention.

FIG. 23 is a side view of the endoscope in FIG. 22 wherein the ‘rearview module’ is deployed for rear view.

FIG. 24A shows side view of an endoscope with a ‘rear view module’according to a ninth embodiment of the present invention. FIG. 24B showsa cross section view of an exemplary biplanar rolling joint that is usedto attach a proximal face of the rear view module to the distal end ofthe endo scope in FIG. 24A.

FIG. 25 is a side view of the endoscope in FIG. 24A wherein the ‘rearview module’ is deployed for rear view.

FIG. 26 shows side view of an endoscope with a ‘rear view module’according to a tenth embodiment of the present invention.

FIG. 27 is a side view of the endoscope in FIG. 26 wherein the ‘rearview module’ is deployed for rear view.

FIG. 28 shows side view of an endoscope with a ‘rear view module’according to an eleventh embodiment of the present invention.

FIG. 29 is a side view of the endoscope in FIG. 28 wherein the ‘rearview module’ is deployed for rear view.

FIG. 30 shows side view of an endoscope with a ‘rear view module’according to a twelfth embodiment of the present invention.

FIG. 31 is a side view of the endoscope in FIG. 30 wherein the ‘rearview module’ is deployed for rear view.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the preferred embodiments of theinvention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts. Thefollowing general description applies to preferred embodiments of thepresent invention.

The present invention comprises of a rear view module. It is a solidstructure that can be rectangular, square, tubular, discoid or of anyother shape. It is attached to a conventional endoscope by a suitablemechanical articulation such as ball socket joint, hinge joint, biplanarrolling joint etc. The rear view module consists of a rear image lens toobtain a rear view. The rear image lens is attached to an imageprocessor by an electric cable. This cable transmits the image obtainedby the rear image lens to the image processor. After being processed,the image is then viewed on a computer monitor or any other displayunit.

The rear view module also contains a rear illumination bulb. The rearillumination bulb is connected to a power source by a cable. The rearillumination bulb uses this light to illuminate the area under view ofthe rear image lens. The rear image lens and the rear illumination bulbare typically activated upon deployment of the rear view module. Therear view module is deployed using an actuator.

A rear instrument channel is provided in the present invention. It isplaced proximal to the rear view module. This channel is connected tothe main instrument channel and the passage is controlled by a controlvalve. Typically, deployment of the rear view module opens the passageto the rear instrument channel. The rear instrument channel is used topass surgical instruments to do various surgical procedures in areasunder view of the rear image lens. It is also used to apply suction inthe area under view of the rear image lens.

A rear air/water channel is provided in the present invention. It isplaced proximal to the rear view module. The rear air/water channel isconnected to the air/water channel of the main endoscope and the passageis controlled by a valve. Typically, deployment of the rear view moduleopens the passage to the rear air/water channel. The rear air/waterchannel is used to insufflate air in the direction of view of the rearimage lens for better distension and visualization. The air/waterchannel is also used to squirt water or air at the rear image lens andthe rear illumination bulb. This enables cleaning of the rear image lensand the rear illumination bulb while still inside a hollow body organ.

FIGS. 1 and 2 illustrate an embodiment of a conventional endoscope. Ithas a handle (4) from which extends a flexible shaft (1), which isinserted into a hollow organ to be inspected. The shaft consists of aproximal section (10), insertion tube (6), bending section (12) and astiff section (13). The shaft terminates in the distal end (14), whichtypically houses one image lens (20), one to two illumination bulbs(21), air/water nozzle (22) and an instrument channel outlet (23). Lightis transmitted from a light source through the shaft via an electriccable (26) to the illumination bulb (21). The illumination bulbilluminates the area to be examined. The image lens (20) captures imagesof the illuminated area. The image is then transmitted through a fiberoptic cable (27) and viewed through an eyepiece (2) attached to thehandle of the endoscope. Alternatively, the image is converted to avideo signal and is then transmitted to an image processor by anelectrical cable. The image is processed and displayed on a display unitlike a computer monitor (not shown). The handle (4) of the endoscope hasa grip (16) and an extension arm (8) that attaches the endoscope to alight source and an image processor.

To enable the endoscope to maneuver through the turns of a hollow organthe shaft is flexible and incorporates a multitude of wires that attachthe bending portion (12) with actuators (18). Typically, there are twopairs of such wires passing within the shaft, one pair for flexing thebending portion in one plane and the other pair for flexing it in anorthogonal plane. Tension is applied to these wires using the actuators(18) to move the bending portion (12) in various directions.

It is also usual to provide two channels extending between the handleand the distal end of the shaft, an air/water channel (24) and aninstrument channel (25). The air/water channel (24) is used toinsufflate air in a hollow organ to expand it for proper visualization.The air/water channel is connected proximally to an air/water pump (notshown) and to distally to the air/water nozzle (22). It is controlled byan air/water control valve (5) located on the handle (4). The image lens(20) and the illumination bulb (21) are frequently smeared with blood,stool or other body fluids while in a hollow organ. In such a situation,the air/water channel (24) is used to squirt water or blow air at theimage lens (20) and/or illumination bulb (21) in order to clean themwhile still inside a hollow organ. The instrument channel (25) has aninstrument channel inlet (7) proximally and an instrument channel outlet(23) distally. It is used to pass surgical instruments to do varioussurgical procedures. It is also used to apply suction using the suctioncontrol valve (3) located on the handle (4). This suction is useful inremoving fluids, air and other materials from within a hollow organduring examination.

FIG. 3 illustrates the narrow field of vision (31) of about 120 degreesof a conventional endoscope (1). It also shows that conventionalendoscopes are only forward viewing (32).

FIG. 4A shows side view of an endoscope (1) inside colon (41). The colonhas mucosal folds (42). The front side of a mucosal fold blocks the viewof the areas behind it during a typical endoscopic examination. Theseareas form the ‘blind spots’ (43) of a conventional endoscope that lieoutside of the forward field of vision (32).

FIG. 4B shows side view of the retro flexion maneuver (44) of aconventional endoscope (1) inside colon (41). During this maneuver, theendoscope is advanced beyond the mucosal fold (42) to be examined. Thebending portion of the endoscope is then bent to 180 degrees tovisualize the rear side of a mucosal fold (43) during forwardexamination, the view of which is obstructed by its front side during aforward examination.

FIG. 5 shows side view of a first preferred embodiment of the presentinvention. The rear view module (51) is a long thin tubular structureencased in a sheath. It is placed along the periphery of a conventionalendoscope. In the preferred embodiment, the rear view module (51)extends through the entire length of the endoscope but it may beshorter. The rear view module (51) has a distal end (50), stiff section,bending section and proximal section similar to an endoscope. In thepreferred embodiment, the distal end (50), stiff section, bendingsection and proximal section of the rear view module (51) is in syncwith the distal end (14), stiff section, bending section and proximalsection of a conventional endoscope. The distal end (50) of the rearview module has a rear image lens (52) and a rear illumination bulb(53). The rear image lens (52) is connected to an image processor (notshown) and the rear illumination bulb (53) is connected to a powersource (not shown) by electrical cables (54, 55) that run within therear view module (51). Two pairs of cables within the rear view moduleattach the bending section of the rear view module to a rear view moduleactuator. Tension on these cables moves the bending section of the rearview module in vertical and horizontal planes.

In the preferred embodiment, there is a rear air/water channel (58) witha rear air/water nozzle (56) and rear instrument channel (59) with arear instrument channel outlet (57) located proximal to the bendingsection of the rear view module (51). The rear air/water channel (58)provides a jet of water and a stream of air that is used to clean therear image lens (52) and the rear illumination bulb (53). It is alsoused to insufflate air in the field of vision of the rear image lens(52) for better distension and visualization. Surgical instruments arepassed through the rear instrument channel (59) to do various surgicalprocedures in the area under view of the rear image lens (52). It isalso used to direct suction to the area under the view of the rear imagelens (52).

In the preferred embodiment, the rear air/water channel (58) and therear instrument channel (59) is connected to the main air/water channel(24) and the main instrument channel (25) respectively. However, thesemay exist independently. Passage to the rear air/water channel (58) andrear instrument channel (59) from the main air/water channel (24) andmain instrument channel (25) is controlled by a valve or any othersuitable mechanical device. Typically, deployment of the rear viewmodule (51) automatically opens the passage to the rear air/waterchannel (58) and the rear instrument channel (59). Alternatively, thepassageways can be controlled independently.

According to another aspect of the preferred embodiment, there can bemore than one rear view module.

FIG. 6 shows the preferred embodiment in FIG. 5 where the rear viewmodule (51) is retro flexed (60) using the rear view module actuator.With this maneuver, the rear image lens (52) faces backward and providesa rear view. The rear illumination bulb (53) illuminates the area underview of the rear image lens (52). The main image lens of the endoscope(20) provides a front view at the same time when the rear image lens(52) is providing a rear view. However, the operator may choose to haveonly one view at a given time. Because the rear view module is thin,retro flexion can be achieved with a small radius of curvature and thuscan be performed even inside narrow hollow organs.

FIG. 7 shows side view of a second preferred embodiment of the presentinvention. The rear view module (51) is a solid rectangular block with aproximal end (71) and a distal end (50). It is located within the stiffsection of the endoscope. The rear image lens (52) and the rearillumination bulb (53) are located on the proximal end (71) of the rearview module. The rear image lens (52) is connected to an image processorand the rear illumination bulb (53) is connected to a power source byelectric cables (54, 55). The distal end (50) of the rear view module isattached to the distal end (14) of the endoscope by a hinge joint or anyother suitable mechanical articulation. The distal end (50) of the rearview module is connected to a rear view module actuator by a pair ofcables (not shown). Tension on these cables moves the rear view moduleaway from and towards the shaft of the endoscope as shown in FIG. 8.

In the preferred embodiment, there is a rear air/water channel (58) witha rear air/water nozzle (56) and rear instrument channel (59) with arear instrument channel outlet (57) located proximal to the rear viewmodule (51). The rear air/water channel (58) provides a jet of water anda stream of air that is used to clean the rear image lens (52) and therear illumination bulb (53). It is also used to insufflate air in thefield of vision of the rear image lens (52) for better distension andvisualization. Surgical instruments are passed through the rearinstrument channel (25) to do various surgical procedures in the areaunder view of the rear image lens (52). It is also used to directsuction to the area under the view of the rear image lens (52).

In the preferred embodiment, the rear air/water channel (58) and therear instrument channel (59) is connected to the main air/water channel(24) and the main instrument channel (25) respectively. However, thesemay exist independently. Passage to the rear air/water channel (58) andrear instrument channel (59) from the main air/water channel (24) andmain instrument channel (25) is controlled by a valve or any othersuitable mechanical device. Typically, deployment of the rear viewmodule (51) automatically opens the passage to the rear air/waterchannel (58) and the rear instrument channel (59). Alternatively, thepassageways can be controlled independently.

FIG. 8 is a side view of the endoscope in FIG. 7 where the rear viewmodule (51) has been deployed by lifting its proximal end (71) away fromthe shaft using the rear view module actuator. When fully deployed, therear image lens (52) and the rear illumination bulb (53) face backward.The image captured by the rear image lens (52) is transmitted to animage processor. The rear illumination bulb (53) illuminates the areaunder view of the rear image lens (52). The main image lens (20) is ableto give a forward view at the same time as the rear image lens is givinga rear view. Forward and rear view can thus be obtained simultaneouslyif so desired by the operator. A major advantage of this embodiment isthat it makes rear view possible requiring only minimal additionalspace. This is of particular advantage when examining narrow bodycavities.

FIG. 9 shows side view of a third preferred embodiment of the presentinvention. The rear view module (51) is a solid rectangular block with aproximal (71) and distal (50) end. It is located within the stiffsection of the endoscope. The rear image lens (52) and the retroillumination bulb (53) are placed on the proximal end (71) of the rearview module. The rear image lens (52) is connected to an image processorand the rear illumination bulb (53) in connected to a power source byelectric cables (54, 55). The rear view module rests on a supportpillar/spring (91). The support pillar/spring can be extended andretracted perpendicular to the shaft of the endoscope. It is attached toa rear view module actuator by cables.

In the preferred embodiment, there is a rear air/water channel (58) witha rear air/water nozzle (56) and rear instrument channel (59) with arear instrument channel outlet (57) located proximal to the rear viewmodule (51). The rear air/water channel (58) provides a jet of water anda stream of air that is used to clean the rear image lens (52) and therear illumination bulb (53). It is also used to insufflate air in thefield of vision of the rear image lens (52) for better distension andvisualization. Surgical instruments are passed through the rearinstrument channel (25) to do various surgical procedures in the areaunder view of the rear image lens (52). It is also used to directsuction to the area under the view of the rear image lens (52).

In the preferred embodiment, the rear air/water channel (58) and therear instrument channel (59) is connected to the main air/water channel(24) and the main instrument channel (25) respectively. However, thesemay exist independently. Passage to the rear air/water channel (58) andrear instrument channel (59) from the main air/water channel (24) andmain instrument channel (25) is controlled by a valve or any othersuitable mechanical device. Typically, deployment of the rear viewmodule (51) automatically opens the passage to the rear air/waterchannel (58) and the rear instrument channel (59). Alternatively, thepassageways can be controlled independently.

FIG. 10 shows the endoscope in FIG. 9 where it has been deployed bymoving the support pillar/spring (91) vertically from the shaft usingthe rear view module actuator. In this position, the rear image lens(52) and the rear illumination bulb (53) face backward. The rear imagelens (52) provides a rear view and the rear illumination bulb (53)illuminates the area under the view of the rear image lens (52). Themain image lens (20) is able to provide a forward view at the same timewhen the rear image lens (52) is providing a rear view. This enablessimultaneous forward and rear view if so chosen by the operator. A majoradvantage of this embodiment is that it provides a straight rear viewthat is desirable for certain surgical procedures.

FIG. 11 shows a side view of a fourth preferred embodiment of thepresent invention. The rear view module (51) is made of two sub modules,the rear image module (111) and the rear illumination module (110). Thesub modules are small rectangular solid structures. They are placedwithin the stiff section of the endoscope. The retro image modulecontains the rear image lens (52) and the rear illumination modulecontains the rear illumination bulb (53). The rear image lens (52) isplaced on the proximal end (115) of the rear image module (110) and therear illumination bulb (53) is placed on the proximal end (113) of theretro illumination module (111). The rear image lens (52) is connectedto an image processor by an electric cable (54) and the rearillumination bulb (53) is connected to a power source by an electriccable (55).

In the preferred embodiment, the rear image module (111) and the rearillumination module (110) are embedded within the stiff section of theendoscope. The distal end (114) of the rear image module and the distalend (112) of the rear illumination module are attached to the shaft ofthe endoscope by a hinge joint or any other suitable mechanicalarticulation. The distal ends of the rear image module and of the rearillumination module (112, 114) are also connected to a pair of rear viewmodule actuators by cables. Tension on these cables moves the rear imagemodule (111) and rear illumination module (110) away from and towardsthe shaft as shown in FIG. 12. The rear image module (111) and the rearillumination module (110) are placed at a suitable distance from eachother.

In the preferred embodiment, there is a rear air/water channel (58) witha rear air/water nozzle (56) and rear instrument channel (59) with arear instrument channel outlet (57) located proximal to the rear viewmodule (51). The rear air/water channel (58) provides a jet of water anda stream of air that is used to clean the rear image lens (52) and therear illumination bulb (53). It is also used to insufflate air in thefield of vision of the rear image lens (52) for better distension andvisualization. Surgical instruments are passed through the rearinstrument channel (25) to do various surgical procedures in the areaunder view of the rear image lens (52). It is also used to directsuction to the area under the view of the rear image lens (52).

In the preferred embodiment, the rear air/water channel (58) and therear instrument channel (59) is connected to the main air/water channel(24) and the main instrument channel (25) respectively. However, thesemay exist independently. Passage to the rear air/water channel (58) andrear instrument channel (59) from the main air/water channel (24) andmain instrument channel (25) is controlled by a valve or any othersuitable mechanical device. Typically, deployment of the rear viewmodule (51) automatically opens the passage to the rear air/waterchannel (58) and the rear instrument channel (59). Alternatively, thepassageways can be controlled independently.

According to another aspect of the preferred embodiment the relativepositions of the rear illumination module and the rear image module canbe interchanged. According to another aspect of the preferred embodimentmore than one rear illumination module and/or rear image module can bepresent.

FIG. 12 is a side view of the endoscope in FIG. 11 where the retro imagemodule (111) and the retro illumination module (110) have been deployedby moving their proximal ends (113,115) away from the shaft using therear view module actuators. In this position the rear image lens (52)and the rear illumination bulb (53) face backward and provide a rearview. The main image lens (20) is able to provide a front view at thesame time when the rear image lens is providing a rear view thusenabling a simultaneous front and rear view. A major advantage of thepreferred embodiment is that the rear illumination module (110) can becontrolled independent of the rear image module (111). This may bedesirable in certain situations.

FIG. 13 shows a side view of a fifth preferred embodiment of the presentinvention. The rear view module (51) is a solid rectangular block with aproximal (131) and distal ends (132). It is located within the stiffsection of the endoscope. It contains a rear image lens (52) and a rearillumination bulb (53) placed on the proximal end (131) of the rear viewmodule. The rear image lens (52) is connected to an image processor byan electric cable (54). The rear illumination bulb (53) is connected tothe power source by an electric cable (55). The rear view module (51)rests on a support arm (130) within the stiff section of the endoscope.The support arm (130) also serves as an extension arm that can beextended, retracted and rotated. The distal end (132) of the rear viewmodule is attached to the support arm (130) by a hinge joint or anyother suitable mechanical articulation. It is also connected to a rearview module actuator by cables. Tension on these cables moves the rearview module (51) away from and towards the support arm (130).

In the preferred embodiment, there is a rear instrument channel (59)with a rear instrument channel outlet (57) located proximal to the rearview module (51). It is used to pass surgical instruments to do varioussurgical procedures in areas under view of the rear image lens (52). Itis also used to direct suction to the area under the view of the rearimage lens (52). The main air/water channel (24) is used to clean therear image lens (52) and the rear illumination bulb (53).

In the preferred embodiment, the rear instrument channel (59) isconnected to the main instrument channel (25). However, it may existindependently. Passage to the rear instrument channel (59) from the maininstrument channel (25) is controlled by a valve or any other suitablemechanical device. Typically, deployment of the rear view module (51)will automatically open the passage to the rear instrument channel (59).Alternatively, the passageway can be controlled independently.

In the preferred embodiment, the rear view module is served by the mainair/water channel (24). However a rear air/water channel may beprovided. According to another aspect of the preferred embodiment, anadditional forward image lens and an additional forward illuminationbulb can be present at the distal end (132) of the rear view module.This will widen the forward field of vision. According to another aspectof the present invention, more than one rear view module can be present.

FIG. 14-16 shows side view of the endoscope in FIG. 13 where the rearview module (51) has been deployed for rear view. The support arm (130)is extended forward (140) to an appropriate distance from the distal end(14) of the endoscope as shown in FIG. 14. The rear image lens (52)faces backward in this position and gives a rear view. The rearillumination bulb (53) faces backward and illuminates the area underview of the rear image lens (52). The main image lens (20) is able togive a front view at the same time as the rear image lens (52) is givinga rear view, thus enabling simultaneous front and rear views. The rearview module (51) can be lifted from (150) and retracted towards thesupport arm (130) using the rear view module actuator as shown in FIG.15. In addition, the support arm can be rotated (160) as shown in FIG.16. This increases the rear field of vision.

FIG. 17 shows side view of a sixth preferred embodiment of the presentinvention. The rear view module (51) is a long and thin tubularstructure encased in a sheath. It has a shaft that comprises of a distalend (170), stiff section, bending section and proximal section. Theshaft is attached proximally to a handle (not shown). The handle has anextension that connects the rear view module (51) to an image processorand a power source. Rear image lens (52) and rear illumination bulb (53)are placed on the distal end (170) of the rear view module (51). Therear image lens (52) and the rear illumination bulb (53) are connectedto an image processor and a light source respectively by electricalcables (54, 55). The bending section of the rear view module isconnected to a rear view module actuator by cables. Tension on thesecables moves the bending section in vertical and horizontal planes. Thisentire assembly is thin enough to pass through the main instrumentchannel (25) of the endoscope.

The rear view module (51) is passed through the instrument channel (25)beyond the distal end (14) of the endoscope as shown in FIG. 18.Backward view is obtained by retro flexing (190) the bending portion ofthe rear view module (51) as shown in FIG. 19. In this position, therear image lens (52) and the rear illumination bulb (53) face backward.The rear image lens (52) gives a rear view and the rear illuminationbulb (53) illuminates the area under the view of the rear image lens(52). The main image lens (20) is able to give a forward view at thesame time as the rear image lens (52) is giving a rear view.Simultaneous forward and rear view can thus be obtained if desired bythe operator. The rear image lens (52) and the rear illumination bulb(53) is serviced by the main air/water channel (24).

In a variation of the preferred embodiment, it can have a rear air/waterchannel and/or a rear instrument channel. In another variation to thepreferred embodiment, the rear view module (51) can be passed throughthe rear instrument channel if one is present. In another variation ofthe preferred embodiment, the rear view module is embedded within theshaft of the endoscope. It is extended beyond the distal end of theendoscope and then retro flexed/bent to give a rear view.

FIG. 20 shows side view of a seventh preferred embodiment of the presentinvention. The rear view module (51) is a hollow tubular structure witha proximal end (201) and a distal end (202). It is placed within theperipheral part of the stiff section of the endoscope, parallel to itslong axis. The rear view module (51) is connected along its length tothe stiff section of the endoscope by a hinge joint or any othersuitable mechanical articulation. The rear image lens (52) and the rearillumination bulb (53) are placed on the proximal end (201) of the rearview module. The rear image lens (52) is connected to an image processorand the rear illumination bulb (53) is connected to a power source byelectric cables (54, 55). Two pairs of cables one on the outside and theother on the inside, connect the rear view module to an actuator alongits length. Tension on these cables opens and closes the module like thelid of a box (203) as shown in FIG. 21. When opened, the rear image lens(52) and the rear illumination bulb (53) face backward. The rear imagelens (52) gives a rear view and the rear illumination bulb (53)illuminates the area under view of the rear image lens (52). The mainimage lens (20) of the endoscope is able to give a forward view at thesame time as the rear image lens (52) is giving a rear view. Hence,simultaneous forward and rear view is possible if the operator sodesires.

In the preferred embodiment, there is a rear air/water channel (58) witha rear air/water nozzle (56) and rear instrument channel (59) with arear instrument channel outlet (57) located proximal to the rear viewmodule (51). The rear air/water channel (58) provides a jet of water anda stream of air that is used to clean the rear image lens (52) and therear illumination bulb (53). It is also used to insufflate air in thefield of vision of the rear image lens (52) for better distension andvisualization. Surgical instruments are passed through the rearinstrument channel (25) to do various surgical procedures in the areaunder view of the rear image lens (52). It is also used to directsuction to the area under the view of the rear image lens (52).

In the preferred embodiment, the rear air/water channel (58) and therear instrument channel (59) is connected to the main air/water channel(24) and the main instrument channel (25) respectively. However, thesemay exist independently. Passage to the rear air/water channel (58) andrear instrument channel (59) from the main air/water channel (24) andmain instrument channel (25) is controlled by a valve or any othersuitable mechanical device. Typically, deployment of the rear viewmodule (51) automatically opens the passage to the rear air/waterchannel (58) and the rear instrument channel (59). Alternatively, thepassageways can be controlled independently.

FIG. 22 shows side view of an eighth preferred embodiment of the presentinvention. The rear view module (51) consists of an inflatable balloon(220) or any other inflatable device that is attached to the stiffsection of the endoscope. The balloon is connected to an air pump by athin tube placed within the shaft of the endoscope (not shown). Wheninflated, the balloon (220) has a proximal face (221) and a distal face(222) as shown in FIG. 23. The proximal face (221) of the ballooncontains the rear image lens (52) and the rear illumination bulb (53).Electric cables (54, 55) connect the rear image lens (52) to an imageprocessor and the rear illumination bulb (53) to a power source.

In the preferred embodiment, there is a rear air/water channel (58) witha rear air/water nozzle (56) and rear instrument channel (59) with arear instrument channel outlet (57) located proximal to the rear viewmodule (51). The rear air/water channel (58) provides a jet of water anda stream of air that is used to clean the rear image lens (52) and therear illumination bulb (53). It is also used to insufflate air in thefield of vision of the rear image lens (52) for better distension andvisualization. Surgical instruments are passed through the rearinstrument channel (25) to do various surgical procedures in the areaunder view of the rear image lens (52). It is also used to directsuction to the area under the view of the rear image lens (52).

In the preferred embodiment, the rear air/water channel (58) and therear instrument channel (59) is connected to the main air/water channel(24) and the main instrument channel (25) respectively. However, thesemay exist independently. Passage to the rear air/water channel (58) andrear instrument channel (59) from the main air/water channel (24) andmain instrument channel (25) is controlled by a valve or any othersuitable mechanical device. Typically, deployment of the rear viewmodule (51) automatically opens the passage to the rear air/waterchannel (58) and the rear instrument channel (59). Alternatively, thepassageways can be controlled independently.

Inflating the balloon (220) deploys the rear view module as shown inFIG. 23. When the balloon is fully inflated, the rear image lens (52)and the rear illumination bulb (53) face backwards. The rear image lens(52) gives a rear view and the rear illumination bulb (53) illuminatesthe area under view of the rear image lens (52). The main image lens(20) of the endoscope is able to give a forward view at the same time asthe rear image lens (52) is giving a rear view. Hence, simultaneousforward and rear view is possible if the operator desires so.

In a variation to the present embodiment, there can be an additionalforward image lens and an additional forward illumination bulb placed onthe distal face (222) of the balloon. This will widen the forward fieldof vision when the balloon (220) is inflated.

FIG. 24A shows side view of a ninth preferred embodiment of the presentinvention. The rear view module (51) is a solid disc shaped structurethat has a proximal face (901) and distal face (902). It is mounted onthe distal end (14) of the endoscope. It comprises of a rear image lens(52) and a rear illumination bulb (53) that is placed on the proximalface (901). The rear image lens (52) is connected to an image processorand the rear illumination bulb (53) is connected to a power source byelectrical cables (54, 55). In the preferred embodiment, the rear viewmodule (51) is placed towards the periphery of the distal end (14) ofthe endoscope but it may be placed at anywhere on the distal end (14).The proximal face (901) of the rear view module is attached to thedistal end (14) of the endoscope by a biplanar rolling joint (904) asshown in FIG. 24B. It allows rolling motion of the rear view module inboth vertical and horizontal planes from the distal end (14).Alternatively, the rear view module may be attached using any othersuitable mechanical articulation. As shown in FIG. 24B, a biplanarrolling joint (904) consists of two grooves (907,908) placedorthogonally to each other. A small wheel (906) is placed within thegroove. The outer part of this wheel is movable and the inner part isfixed. The rear view module (51) is attached to the fixed inner part.The rear view module is moved by rotating the wheel (906) along thegrooves (907, 908).

In the preferred embodiment, there is a rear air/water channel (58) witha rear air/water nozzle (56) and rear instrument channel (59) with arear instrument channel outlet (57) located proximal to the rear viewmodule (51). The rear air/water channel (58) provides a jet of water anda stream of air that is used to clean the rear image lens (52) and therear illumination bulb (53). It is also used to insufflate air in thefield of vision of the rear image lens (52) for better distension andvisualization. Surgical instruments are passed through the rearinstrument channel (25) to do various surgical procedures in the areaunder view of the rear image lens (52). It is also used to directsuction to the area under the view of the rear image lens (52).

In the preferred embodiment, the rear air/water channel (58) and therear instrument channel (59) is connected to the main air/water channel(24) and the main instrument channel (25) respectively. However, thesemay exist independently. Passage to the rear air/water channel (58) andrear instrument channel (59) from the main air/water channel (24) andmain instrument channel (25) is controlled by a valve or any othersuitable mechanical device. Typically, deployment of the rear viewmodule (51) automatically opens the passage to the rear air/waterchannel (58) and the rear instrument channel (59). Alternatively, thepassageways can be controlled independently.

The rear view module (51) is deployed by rolling it vertically (903)from the distal end of the endoscope (14), as shown in FIG. 25.Alternatively the rear view module can be deployed by rolling ithorizontally from the distal end (14). The extent of the roll is enoughto move the rear image lens (52) and the rear illumination bulb (53)away from the distal end of the endoscope (14). In this position, therear image lens (52) gives a rear view and the rear illumination bulb(53) illuminates the area under view of the rear image lens (52). Therear view module (51) can also be rotated to widen the rear field ofview. This may cause some distortion of the image which can be correctedby modifying the software of the image processor. The main image lens(20) of the endoscope is able to give a forward view at the same time asthe rear image lens (52) is giving a rear view. Hence, simultaneousforward and rear view is possible if so desired by the operator.

In a variation to the preferred embodiment the rear view module maycontain an additional forward image lens and an additional forwardillumination bulb on its distal face (902). This will widen the forwardfield of vision.

FIG. 26 shows side view of a tenth preferred embodiment of the presentinvention. The rear view module (51) is a solid discoid structure thatis mounted on the distal end of the endoscope (14). It has a proximalface (101) and a distal face (102). The rear view module (51) isattached to the distal end of the endoscope (14) by a hinge joint (103)or any other suitable mechanical articulation. The rear view module (51)has a rear image lens (52) and a rear illumination bulb (53) that ismounted on its distal face (102) of the module. The rear image lens (52)is connected to an image processor and the rear illumination bulb (53)is connected to a power source by electrical cables (54, 55). In restingposition, the rear image lens (52) and the rear illumination bulb faceforward and augment the main image lens (20) and the main illuminationbulb (21) to widen the forward field of view. In the preferredembodiment, the rear view module (51) is placed at the periphery of thedistal end of the endoscope (14) but it can be placed anywhere. The rearview module (51) is connected to a rear view module actuator by cables.Tension on these cables flips the rear view module (51) clockwise andanticlockwise vertically from the distal end of the endoscope (14).Alternatively, the rear view module can be flipped in a horizontalplane.

In the preferred embodiment, there is a rear air/water channel (58) witha rear air/water nozzle (56) and rear instrument channel (59) with arear instrument channel outlet (57) located proximal to the rear viewmodule (51). The rear air/water channel (58) provides a jet of water anda stream of air that is used to clean the rear image lens (52) and therear illumination bulb (53). It is also used to insufflate air in thefield of vision of the rear image lens (52) for better distension andvisualization. Surgical instruments are passed through the rearinstrument channel (25) to do various surgical procedures in the areaunder view of the rear image lens (52). It is also used to directsuction to the area under the view of the rear image lens (52).

In the preferred embodiment, the rear air/water channel (58) and therear instrument channel (59) is connected to the main air/water channel(24) and the main instrument channel (25) respectively. However, thesemay exist independently. Passage to the rear air/water channel (58) andrear instrument channel (59) from the main air/water channel (24) andmain instrument channel (25) is controlled by a valve or any othersuitable mechanical device. Typically, deployment of the rear viewmodule (51) automatically opens the passage to the rear air/waterchannel (58) and the rear instrument channel (59). Alternatively, thepassageways can be controlled independently.

FIG. 27 shows the endoscope on FIG. 26 where the rear view module (51)has been deployed by flipping it vertically (104) from the distal end ofthe endoscope (14) to 180 degrees. In this position, the rear image lens(52) faces backward and gives a rear view. The rear illumination bulb(53) faces backward and illuminates the area under view of the rearimage lens (52). The rear view module (51) can also be rotated indifferent directions to widen the rear field of vision. The main imagelens (20) of the endoscope is able to give a forward view at the sametime as the rear image lens (52) is giving a rear view. Hence,simultaneous forward and rear view is possible if the operator sodesires.

In a variation to the preferred embodiment, the rear view module (51)may also contain an additional forward image lens and an additionalforward illumination bulb on its proximal face (101). This will increasethe forward field of vision when the rear view module is deployed (104)with its proximal face (101) facing forward.

FIG. 28 shows side view of an eleventh preferred embodiment of thepresent invention. The rear view module (51) is a solid discoidstructure that is placed in front of the distal end (14) of theendoscope. The periphery of the rear view module (51) is attached to thedistal end (14) of the endoscope by a hinge joint (285) or any othersuitable mechanical articulation. It has a proximal face (281) and adistal face (282). The rear image lens (52) and the rear illuminationbulb (53) are placed on the distal face (282) of the rear view module.The rear image lens (52) is connected to an image processor and the rearillumination bulb (53) is connected to a power source by electric cables(54, 55). In resting position, the rear view module (51) covers thedistal end of the endoscope (14) and faces forward. In this position,the rear image lens (52) gives a forward view and the rear illuminationbulb (53) illuminates the area in front of the endoscope. In thepreferred embodiment, the diameter of the rear view module (51) is thesame as that of the distal end of the endoscope (14). The air/waterchannel (24) and the instrument channel (25) of the endoscope extendinto the rear view module (283,284). The proximal and distal face of therear view module (281, 282) is connected to a rear view module actuatorby cables. Tension on these cables flips the rear view module (51)clockwise and anti clockwise vertically from the distal end of theendoscope (14) as shown in FIG. 29. Alternatively, the rear view modulecan be flipped horizontally.

In the preferred embodiment, there is a rear air/water channel (58) witha rear air/water nozzle (56) and rear instrument channel (59) with arear instrument channel outlet (57) located proximal to the rear viewmodule (51). The rear air/water channel (58) provides a jet of water anda stream of air that is used to clean the rear image lens (52) and therear illumination bulb (53). It is also used to insufflate air in thefield of vision of the rear image lens (52) for better distension andvisualization. Surgical instruments are passed through the rearinstrument channel (25) to do various surgical procedures in the areaunder view of the rear image lens (52). It is also used to directsuction to the area under the view of the rear image lens (52).

In the preferred embodiment, the rear air/water channel (58) and therear instrument channel (59) is connected to the main air/water channel(24) and the main instrument channel (25) respectively. However, thesemay exist independently. Passage to the rear air/water channel (58) andrear instrument channel (59) from the main air/water channel (24) andmain instrument channel (25) is controlled by a valve or any othersuitable mechanical device. Typically, deployment of the rear viewmodule (51) automatically opens the passage to the rear air/waterchannel (58) and the rear instrument channel (59). Alternatively, thepassageways can be controlled independently.

FIG. 29 shows the endoscope in FIG. 28 where the rear view module (51)has been deployed by flipping it vertically from the distal end of theendoscope to 180 degrees (286) using the rear view module actuator. Inthis position, the rear image lens (52) and the rear illumination bulb(53) face backward. The rear image lens (52) gives a rear view and therear illumination bulb (53) illuminates the area under view of the rearimage lens (52). Further, the rear view module (51) can be rotated inthis position to increase the rear field of view. Upon deployment, therear view module (51) moves away from the front of the distal end (14)of the endoscope. It enables the main image lens (20) to give a forwardview and the main illumination bulb (21) to illuminate the area in frontof the distal end of the endoscope. This makes it possible to havesimultaneous forward and rear view if so desired by the operator.

In a variation to the preferred embodiment, the rear view modulecontains an additional forward image lens and an additional forwardillumination bulb on its proximal face (281). When the rear view moduleis deployed, the proximal face (281) with the additional forward imagelens and additional illumination bulb faces forward and augments themain image lens (20) and the main illumination bulb (21. This widens theforward field of vision when the rear view module is deployed.

FIG. 30 shows side view of a twelfth preferred embodiment of the presentinvention. The rear view module (51) is a solid discoid structure thatis placed in front of the distal end of the endoscope (14). It has aproximal face (301) and a distal face (302). The rear view modulecomprises of a rear image lens (52) connected to an image processor anda rear illumination bulb (53) connected to a power source by electriccables (54, 55). The rear image lens (52) and the rear illumination bulb(53) are placed on the proximal face (301) of the rear view module (51).In addition, the rear view module (51) has an additional image lens(303) and an additional illumination bulb (304) that is placed on itsdistal face (302). In the preferred embodiment, the diameter of the rearview module (51) is the same as that of the distal end of the endoscope(14). The main air/water channel (24) and the main instrument channel(25) of the endoscope extend into the rear view module (305, 306). Therear view module (51) is attached to the distal end of the endoscope(14) by a biplanar rolling joint as shown in FIG. 24B. This allowsrolling motion of the rear view module (51) both vertically andhorizontally to the distal end of the endoscope (14). It may also beattached by any other suitable mechanical articulation. In restingposition, the rear view module (51) covers the main image lens (20) andthe main illumination bulb (21) of the endoscope. In this position, theadditional image lens (303) and the additional illumination bulb (304)faces forward and gives a forward view and illuminates the area in frontof the endoscope.

In the preferred embodiment, there is a rear air/water channel (58) witha rear air/water nozzle (56) and rear instrument channel (59) with arear instrument channel outlet (57) located proximal to the rear viewmodule (51). The rear air/water channel (58) provides a jet of water anda stream of air that is used to clean the rear image lens (52) and therear illumination bulb (53). It is also used to insufflate air in thefield of vision of the rear image lens (52) for better distension andvisualization. Surgical instruments are passed through the rearinstrument channel (25) to do various surgical procedures in the areaunder view of the rear image lens (52). It is also used to directsuction to the area under the view of the rear image lens (52).

In the preferred embodiment, the rear air/water channel (58) and therear instrument channel (59) is connected to the main air/water channel(24) and the main instrument channel (25) respectively. However, thesemay exist independently. Passage to the rear air/water channel (58) andrear instrument channel (59) from the main air/water channel (24) andmain instrument channel (25) is controlled by a valve or any othersuitable mechanical device. Typically, deployment of the rear viewmodule (51) automatically opens the passage to the rear air/waterchannel (58) and the rear instrument channel (59). Alternatively, thepassageways can be controlled independently.

FIG. 31 shows the endoscope in the embodiment in FIG. 30 where the rearview module (51) has been deployed by sliding it vertically (307) fromthe distal end of the endoscope (14). Upon deployment, the rear imagelens (52) and the rear illumination bulb (53) face backward. The rearimage lens (52) gives a rear view and the rear illumination bulb (53)illuminates the area under view of the rear image lens (52). Further,the rear view module (51) can be rotated to increase the field of rearview. The rear view module (51) also moves away from front of the distalend of the endoscope (14) upon deployment. The main image lens (20) isthen able to give a forward view and the main illumination bulb (21) isable to illuminate the area in front of the endoscope. Hence, thepreferred embodiment provides simultaneous forward and rear view if sodesired by the operator. The additional image lens (303) and theadditional illumination bulb (304) augment the main image lens (20) andthe main illumination bulb (21) and widen the forward field of visionwhen the rear view module (51) is deployed.

Any person/persons familiar with prior art will understand thatmodifications or changes to the present invention can be made withoutcompromising its principles. In one variation of the present invention,the relative positions of the rear view module, rear air/water channeland the rear instrument channel may be changed. In another variation ofthe present invention, more than one rear view module, rear instrumentchannel and rear air/water channel can be present. According to anothervariation of the present invention, the rear view module, rearinstrument channel and the rear air/water channel can be placed anywhereon the endoscope. According to yet another variation of the presentinvention, the shape, composition and configuration of the rear viewmodule can be modified or changed without compromising the basicprinciples of the present invention. According to another variation ofthe present invention, the method of deployment of the rear view modulecan be modified without compromising the basic principles of the presentinvention. According to yet another variation of the present inventionmore than one rear image lens and/or more than one rear illuminationbulb can be present. The above examples are only illustrative and by nomeans all inclusive.

What is claimed is:
 1. An endoscope used to perform gastrointestinalendoscopy, the endoscope comprising: a shaft having a distal endreceivable in a hollow gastrointestinal tract and a proximal end, theshaft extending from the distal end along a longitudinal axis towardsthe proximal end, the distal end and the proximal end defining a hollowchannel extended therethrough, the hollow channel connected to andopening to one or more outlets on the distal end; a forward view modulecomprising a first lens positioned adjacent to the distal end of theshaft, the forward view module configured to have a forwardfield-of-vision when receiving a first image through the first lenswhile the distal end of the shaft is being received in the hollowgastrointestinal tract, the forward field-of-vision including a zerodegree angle to the longitudinal axis in a forward direction pointingfrom the proximal end of the shaft to the distal end of the shaft; and arearview module comprising a second lens, the rearview module disposedon the outer periphery of the shaft adjacent to the distal end of theshaft and configured to have a rearward field-of-vision when receiving asecond image through the second lens when the distal end of the shaft isbeing received in the hollow gastrointestinal tract, the rearwardfield-of-vision including an acute angle to the longitudinal axis in arearward direction pointing from the distal end of the shaft to theproximal end of the shaft; and a rearview air/water channel having arearview air/water outlet, the rearview air/water outlet located on theouter periphery of the shaft and adjacent to the second lens, therearview air/water channel configured to channel at least one of a waterjet and an air stream out of the rearview air/water outlet in such amanner that the channeled at least one of the water jet and the airstream is directed to clean at least the second lens while the distalend of the shaft is being received in the hollow gastrointestinal tractand the forward view and rearview modules are being respectivelyconfigured to receive the first and second images; wherein the rearviewmodule receives the second image substantially simultaneously with theforward view module receiving the first image; wherein one portion ofthe rearview air/water channel is situated and extended inside thehollow channel extended through the distal and proximal ends of theshaft; wherein the one or more outlets on the distal end of the shaftincludes a main air/water outlet; wherein the endoscope furthercomprises a main air/water channel having the main air/water outlet, oneportion of the main air/water channel situated and extended inside thehollow channel, the main air/water channel configured to channel,through the main air/water outlet, water or air into the hollowgastrointestinal tract; and wherein the one portion of the rearviewair/water channel situated and extended inside the hollow channel isincluded within the one portion of the main air/water channel situatedand extended inside the hollow channel.
 2. The endoscope of claim 1,wherein the rearview module is configured to transition from having aninitial field-of-vision during an undeployed state to having therearward field-of-vision during a deployed state.
 3. The endoscope ofclaim 1, wherein the rearview module is attached to the distal end ofthe shaft during an undeployed state before the rearview module isdeployed to a deployed state during which the rearview module isconfigured to have the rearward field-of-vision, when the distal end ofthe shaft is being received in the hollow gastrointestinal tract.
 4. Theendoscope of claim 1, wherein the rearview module is disposed adjacentto the distal end of the shaft through an independent steering systemwhen the distal end of the shaft is being received in the hollowgastrointestinal tract.
 5. The endoscope of claim 1, wherein therearview module is configured to transition from an undeployed state toa deployed state during which the rearview module is configured to havethe rearward field-of-vision, through an actuating mechanism.
 6. Theendoscope of claim 1, further comprising: a rearview instrument channelhaving a rearview instrument outlet located on the outer periphery ofthe shaft and adjacent to the rearview module, the rearview instrumentchannel configured to pass, through the rearview instrument outlet,instruments to do surgical procedures in an area within the rearwardfield-of-vision of the rearview module.
 7. The endoscope of claim 6,wherein one portion of the rearview instrument channel is situated andextended inside the hollow channel extended through the distal end andthe proximal end of the shaft.
 8. The endoscope of claim 6, wherein theone or more outlets on the distal end of the shaft includes a maininstrument outlet; and wherein the endoscope further comprises a maininstrument channel having the main instrument outlet, one portion of themain instrument channel situated and extended inside the hollow channel,the main instrument channel configured to pass, through the maininstrument outlet, instruments to do surgical procedures in the hollowgastrointestinal tract.
 9. The endoscope of claim 8, wherein therearview instrument channel is extended inside the hollow channelindependent of the main instrument channel.
 10. The endoscope of claim8, wherein the rearview instrument channel is connected to the maininstrument channel.